path: root/fs/fuse/dir.c

/*
  FUSE: Filesystem in Userspace
  Copyright (C) 2001-2008  Miklos Szeredi <miklos@szeredi.hu>

  This program can be distributed under the terms of the GNU GPL.
  See the file COPYING.
*/

#include "fuse_i.h"

#include <linux/pagemap.h>
#include <linux/file.h>
#include <linux/gfp.h>
#include <linux/sched.h>
#include <linux/namei.h>

#if BITS_PER_LONG >= 64
static inline void fuse_dentry_settime(struct dentry *entry, u64 time)
{
	entry->d_time = time;
}

static inline u64 fuse_dentry_time(struct dentry *entry)
{
	return entry->d_time;
}
#else
/*
 * On 32 bit archs store the high 32 bits of time in d_fsdata
 */
static void fuse_dentry_settime(struct dentry *entry, u64 time)
{
	entry->d_time = time;
	entry->d_fsdata = (void *) (unsigned long) (time >> 32);
}

static u64 fuse_dentry_time(struct dentry *entry)
{
	return (u64) entry->d_time +
		((u64) (unsigned long) entry->d_fsdata << 32);
}
#endif

/*
 * FUSE caches dentries and attributes with separate timeout.  The
 * time in jiffies until the dentry/attributes are valid is stored in
 * dentry->d_time and fuse_inode->i_time respectively.
 */

/*
 * Calculate the time in jiffies until a dentry/attributes are valid
 */
static u64 time_to_jiffies(unsigned long sec, unsigned long nsec)
{
	if (sec || nsec) {
		struct timespec ts = {sec, nsec};
		return get_jiffies_64() + timespec_to_jiffies(&ts);
	} else
		return 0;
}

/*
 * Set dentry and possibly attribute timeouts from the lookup/mk*
 * replies
 */
static void fuse_change_entry_timeout(struct dentry *entry,
				      struct fuse_entry_out *o)
{
	fuse_dentry_settime(entry,
		time_to_jiffies(o->entry_valid, o->entry_valid_nsec));
}

static u64 attr_timeout(struct fuse_attr_out *o)
{
	return time_to_jiffies(o->attr_valid, o->attr_valid_nsec);
}

static u64 entry_attr_timeout(struct fuse_entry_out *o)
{
	return time_to_jiffies(o->attr_valid, o->attr_valid_nsec);
}

/*
 * Mark the attributes as stale, so that at the next call to
 * ->getattr() they will be fetched from userspace
 */
void fuse_invalidate_attr(struct inode *inode)
{
	get_fuse_inode(inode)->i_time = 0;
}

/*
 * Just mark the entry as stale, so that a next attempt to look it up
 * will result in a new lookup call to userspace
 *
 * This is called when a dentry is about to become negative and the
 * timeout is unknown (unlink, rmdir, rename and in some cases
 * lookup)
 */
void fuse_invalidate_entry_cache(struct dentry *entry)
{
	fuse_dentry_settime(entry, 0);
}

/*
 * Same as fuse_invalidate_entry_cache(), but also try to remove the
 * dentry from the hash
 */
static void fuse_invalidate_entry(struct dentry *entry)
{
	d_invalidate(entry);
	fuse_invalidate_entry_cache(entry);
}

static void fuse_lookup_init(struct fuse_conn *fc, struct fuse_req *req,
			     u64 nodeid, struct qstr *name,
			     struct fuse_entry_out *outarg)
{
	memset(outarg, 0, sizeof(struct fuse_entry_out));
	req->in.h.opcode = FUSE_LOOKUP;
	req->in.h.nodeid = nodeid;
	req->in.numargs = 1;
	req->in.args[0].size = name->len + 1;
	req->in.args[0].value = name->name;
	req->out.numargs = 1;
	if (fc->minor < 9)
		req->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
	else
		req->out.args[0].size = sizeof(struct fuse_entry_out);
	req->out.args[0].value = outarg;
}

u64 fuse_get_attr_version(struct fuse_conn *fc)
{
	u64 curr_version;

	/*
	 * The spin lock isn't actually needed on 64bit archs, but we
	 * don't yet care too much about such optimizations.
	 */
	spin_lock(&fc->lock);
	curr_version = fc->attr_version;
	spin_unlock(&fc->lock);

	return curr_version;
}

/*
 * Check whether the dentry is still valid
 *
 * If the entry validity timeout has expired and the dentry is
 * positive, try to redo the lookup.  If the lookup results in a
 * different inode, then let the VFS invalidate the dentry and redo
 * the lookup once more.  If the lookup results in the same inode,
 * then refresh the attributes, timeouts and mark the dentry valid.
 */
static int fuse_dentry_revalidate(struct dentry *entry, struct nameidata *nd)
{
	struct inode *inode = entry->d_inode;

	if (inode && is_bad_inode(inode))
		return 0;
	else if (fuse_dentry_time(entry) < get_jiffies_64()) {
		int err;
		struct fuse_entry_out outarg;
		struct fuse_conn *fc;
		struct fuse_req *req;
		struct fuse_req *forget_req;
		struct dentry *parent;
		u64 attr_version;

		/* For negative dentries, alway